Although previous research on age-related changes in immune function have concentrated on the deficiency of factors that augment cellular function, it is now apparent that the levels of many lymphokines, cytokines, and inflammatory factors are elevated in serum and spleen cell culture supernatants from old mice. These factors, IL-6 TGFbeta TNF and IFNgamma can disrupt cellular function. The causes of the elevations are not known, but demonstrate that old mice and their cells are not deficient in their ability to make factors. In old rats, factors such as TGFbeta and IL-6 may explain the differences seen in bone marrow cellular response to trauma, and IL-6 has been reported to prevent osteoporosis.